Projection screens are widely used for business, educational and entertainment purposes. However, in places such as conference rooms, meeting facilities, hospitality suites, etc., projection screens may only be used occasionally, such that the need for an exposed projection screen is limited. In those environments, facility owners/managers often prefer not to have the projection screen exposed when not in use, to avoid harm to the projection surface or to otherwise detract from the aesthetics of the room. One solution that has been available is a retractable screen.
Flexible, retractable projection screen surfaces, typically made of materials such as fabric or vinyl, generally deploy from a roller located in a ceiling-recessed or ceiling-mounted housing. When in use, the viewing surface is extended or lowered from the housing to an appropriate level. This viewing level is properly determined by known ideal angles of view with regard to ergonomic factors such as eye and neck strain.
In large venues such as hotel ballrooms, convention centers or houses of worship, the high ceiling elevations require that the projection screens be lowered a fairly significant distance from the ceiling. In those installations, the retractable screen is fixed to a large length of black fabric known as “black drop” in order to bring the viewing area down to proper level (see FIG. 1 hereto). However, the use of black drop is not favored because it visually detracts from the room décor, may wrinkle or tear during retraction, etc.
Some screen manufacturers have addressed the deficiencies of “black drop” by adding an electric hoist mechanism which lowers a screen case containing the screen, roller and retraction mechanism from the ceiling to a suitable viewing level. The screen contained in the screen case is then deployed from the screen case by a separate roller motor.
This method is employed in two existing forms. In the first, a motorized hoist is fixed to a structure on or recessed into the ceiling with cables attached to the screen case, so that the hoist draws the screen case up to the ceiling. In the second, the motorized hoist is housed inside of the screen case with the cables attached to fixed points on or within the structure of the ceiling, so that the hoist draws the screen case to the ceiling. Both of these methods, however, involve the disadvantage of two separate motor systems, one for the hoist and the other for the screen roller, increasing cost, weight, complexity, maintenance and points of failure.